Sound recording device



P 2, 1941- A. BADMAIEFF I 2,254,412

SOUND RECORDING DEVICE Filed June 10, 1940 Z'Sheets-Sheet l INVENTOR ATTORNEY Sept. 2, 1941. A. BADMAIEFF I 4,

SOUND RECORDING DEVICE Filed June '10, 1940 2 Sheets-Sheet 2 I 25 2e Y 35 24 INVENTOR A2 zx/s EAQ/M/EFF ATTORNEY v Patented Sept. 2, 1941- OFFICE 2,254,412 soUNn nacon'nmc. DEVICE Alexis Badmaiefl', Ins Angeles, Calif. Application June r0, 1940, Serial No. 339,609

scams.

This invention relates to sound recording apparatus, particularly to apparatus adapted to cut a groove in a disc of wax acetate 'or other composition, this disc being subsequently employed for the production of a matrix and the manufacture of a plurality 'of records therefrom or for immediate reproduction directly from the acetate or other composition record. More particularly, the invention pertains to a simple and efficientarrangement of elements whereby sound recorders may be produced in large quantity for home use.

In constructing sound recording equipment of this general type, it has been customary in the past to-provide the apparatus with heavy, very accurately cut. lead screws and with a rigid stylus arm moved by such lead screws, the stylus arm being then provided with a cutting head at its end. These prior devices were heavy, cumber-' some and extremely expensive. The present invention is particularly directed to a simplified construction involving a minimum amount of machine work in itsproduction, and permitting the use of lightweight die cast or molded parts so that the cost of the recorders is reduced to a minimum, and such recording devices are capa' ble of being manufactured vin large quantities and assembled with the minimum of efl'ort.

The construction and arrangement ofthe devices forming the subject matter of. this invention include theprovision of means for controlling and altering the speedof the disc upon which the recording is being made. Another desirable feature of the present invention involves the provision of means whereby the depth of the groove cut by the stylus in the disc is" readily controlled. The device of the present invention permits recording to be made either from the perimeter of the disc inwardly or from a central area of the disc outwardly. Means have also been provided for regulatably controlling the pressure of the stylus on the disc.

It is therefore an object of this invention to provide an improved means for traversing the stylus across the face of a disc upon which the record is being produced.

. parent as the description proceeds. For purposesof illustration reference will be had to the appended drawings in which:

Fig. 1 is a plan of the recorder embodying one form of the present invention,

Fig. 2 is a vertical section of the device of Fig.

its mounting.

The device illustrated and described is spe- --cifl cally adapted to cutting a wavy line (side stood that with certain modifications it can be utilized for other types of record. A supporting base or framework l carries mounted thereon for rotation a turntable 2, having a bearing 3 and a shaft 4 extending below the base, the end of the shaft being carried in an outboard bearing 5 at the lower end. A pulley 6 is mounted on shaft 4 and keyed or otherwise secured to rotate with shaft 4.

. As a driving means for the turntable, a motor I is-provided. This motor is mounted in any suitable manner to' slide or pivot about a vertical axis, so that its distance from the inner surface of the downwardly extending flange of disc 2 5 may be varied. In the present instance this is accomplished by the provision of members 8 and 9 secured to the underside of the base I, and

member l0 having portions II and i2 engaging bores in members 8 and 9 for sliding movement 40 therein. "A lever l3, suitably linked to the sliding member It! provides a'means for controllin the position of the member l0. Themotor 1 is secured to the member III by any suitable means. As a driving connection between the shaft ll of the constant speed motor 1 and the turntable,

a friction pinion l5 may be used, and the inner face of the peripheral flange 16 of the turntable may be faced with any suitable friction material H, such as rubber or fibre. In order that differtained, pinion I! may have two metal-faced portions it and I 9 of different diameters adapted to alternatively engage the inner face of the peripheral flange It. This may be accomplished in a number of ways, perhaps the simplest being Fig. 7 is an elevation of the driving motor and wall type) record, although it is to be underent speeds of rotation of the disc may be obto arrange the pinion l and shaft |4 so that the pinion may be removed, turned end for end, and replaced, thus bringing either portion into position to engagethe flange l6. Or; if desired, the

larger portion it may be arranged to slide over ber It, may be connected to a suitabletoggle switch, so that movement of the pinion i5 away from er gagement with the flange is accompanied by the legs of the two U-shaped members, a layer of friction material such as leather may be applied to one or both of the corresponding faces engaging the lays of the band, as shown at 4linFig. 5.

by a sh itting oil of the power supply to the motor I.

For producing the record on the disc, a recording head 2 l, equipped with a cutting stylus 22 is provided.

carries a pulley 22. The two shafts 25 and,"

are connected together for driving of shaft 22 by shaft 25, by the provision of a worm 22 on shaft 25, and the worm gear 2| on shaft 28, the

' two meshing..

At a distance from member 21 there is mounted a second support 22, which carries a second pulley 23, mounted in such a position with respect to pulley 29 that an endless belt or band 24 can be driven upon rotation of pulley 22. This belt is preferably formed of a thin, flexible, metallic strip. In order to keep proper tension on the belt or band 24, and prevent slipping, pulley 22 is preferably resiliently mounted, for movement toward and away from pulley 22. This is most simply accomplished by providing the pulley bracket 35 mounted for sliding movement on support 32, and a small coil' spring between the bent-over end 26 of the bracket and a portion of the support 22, the spring being under compression to force the bracket, and the pulley 32 with it, away from pulley 29. The band 24 is thus kept under tension. Thus, it is seen that a band has been provided, which moves in the proper direction to cause the stylus arm to traverse the turntable as the table is rotated.

In order to properly mount the stylus arm 22 for motion by the band 24, a pair of guide rails 31 and 28 are secured to' the supports 21 and 32. On these guide rails 21. and 22 there is mounted a carriage 29 for sliding movement along the rails. Secured to the. carriage is the U-shaped member 42, having the leg 4| immediately above the upper lay and the leg 42 immediately' below the lower lay of band 24, as shown in Figs.-5 and 6. Between the legs 4| and 42, and within the lays, of the band 24, is a second U-shaped member 48 having legs 44 and 45. This member is mounted for vertical sliding in any suitable manner, here illustrated This head is mounted to traverse the face of the disc being operated'upon by means of the stylus arm 22, which is so arranged as to progress over the face of the disc as the tum- Any suitable means may be used to control the position of the sliding plate 48. In the form shown, a shaft 48 is journaled in the carriage 22, and has a small pin 49 in its end set eccentrically to the axis of the shaft. This pin 42 engages a slot 50 in sliding plate 46, so that upon rotation of the shaft, the plate 44 will be driven in an upward or a downward direction. In order to facilitate rotation of the shaft, and also to serve as an indication ofthe direction in which the carriage will travel, a handle 5| may be keyed to the shaft 48.

The stylus arm 22 is not mounted or supported on the carriage above described, but slides on the upper guide rail 31, and is merely driven by the carriage, as will appear. The stylus arm consists of the long arm 52, a crossarm 52 and a short arm 54. The crossarm 52 has a projecting ear 55 projecting downwardly and furnished with a bore through which passes the guide rod 21. A corresponding ear 56 is furnished on the long arm 52, also equipped with a bore for the passage of the guide rail, and the two cooperate to support the entire stylus arm 22 on the rail 21, but permit it to rotate about the axis of the rail, to permit the arm to be lifted to facilitate the chang g of record discs, and to permit the stylus 22 to be placed in a selected position on the face of the disc. The short arm 54 is equipped with a counterweight to nearlybalance theweight of the long arm and recorder head 2|.

In order that the carriage drive the stylus arm, a compression spring 52 may be placed between the car 51 and the carriage, as shown in Fig. 2. The ear- 56 engages a portion of carriage 29, and is held thereagainst by the spring 58,.thus insuring at all times that the parts are accurately positioned. The force of spring 52 is sufllcient to maintain the driving carriage 5 firmly against the ears of the stylus arm and may pivot as a whole about an axis passing as being mounted on a plate 86 which slides between the carriage 28 and a cut-out portion of the U.-shapcd member 40. It can be seen. that bracket 60.

through the point of pivotal attachment of the 7 As shown' in Figs. 3 and 4. the bracket is pivoted to the stylus'arm by means of studs 6| passing through the walls of the stylus arm and into holes in the bracket.

With such pivotal arrangement, the entire weightof the recording head would rest upon the stylus 22, which in many cases is too great pressure for proper recording. At the same time,

nothing which has heretofore been described supports the weight of the stylus arm 23 counterbalanced to some extent by the weight W. To provide for these, a movable shoe 62, polished and adapted to slide upon the surface of the disc placed on either side of the stylus. With this arrangement, the shoe 62 can always ride on the uncut side of the disc, to avoid interference because of chips and burrs on the out side, and also to preserve the out side from damage. The position of the shoe can be adjusted, to take care of differences in lengths of the stylus 22 by means of screw 65, working in a tapped hole in the stylus arm; The end of this screw engages the elongated member 63 on the side of the notch 66 out therein, the purposeof the'notch being merely to provide a bearing surface for the end of the screw, to prevent any tendency to bend the screw or cause a jammingof the screw and the member 63. In order to hold the elongated member 63 in its adjusted position against the screw 65, a leaf spring 61 is attached to the shaft 64, and bears against shaft 68, the flexibility of the spring permitting the screw to be adjusted but keeping the member 63 thereagainst.

With the shoe 62 supporting the weight of the stylus arm, the weight of the recorder head 2|- still rests entirely, or nearly so, upon the point of the stylus 22. In order to provide a variable, lighter contact on the disc, a spring 69 is attachedto the-bracket 60,. in such a manner that its tension tends to counterbalance the weight of the recorder head 2!. This isclearly shown in Fig. 3. In order to vary the tension of the spring, and thus vary the uncounterbalanced weight resting on the point of the stylus, a flexible cable ll! is attached to the spring, and the cable wound about shaft 68 mentioned above. Winding the cable will naturally increase the tension of the spring, and remove some of the weight from the point of the stylus 2|. Suitable face plates, said movable face plates being fixed relative to each other, and said stationary and said movable face plates being so arranged that movement of the movable plates in one direction causes one of the lays of said band to be engaged by one of said stationary and one of said movable face plates, and movement of the movable plates in the other direction causes engagement of the other lay of said band by the other two face plates.

2. In a sound recording machine the combination of: a stationary frame including a pair of horizontally disposed guide rails; a pulley rotatably mounted at each end of said frame; a flexible continuous metallic belt carried by said pulleys; a driving carriage slidably mounted on said guide rails: a clutch on said carriage, said clutch being adapted to selectively engage and hold either lay of said belt, said clutch comprising a pair of statween the lays of said belt; and lever actuated cam means for actuating said movable face plates to selectively engage the belt between a stationary face plate and a movable face plate.

y 3. In a reversible drive for the stylus arm of a sound recording machine including a rotatable disc table, the combination of: horizontally disposed guide means to one side of said table and substantially on the level of a disc on said table; a pulley rotatably disposed at each end of said guide means; a flexible continuous band carried by said pulleys, aclutch including a movable member selectively movable to engage and hold either lay of, said band, and means connecting said clutch to a stylus arm whereby motion of the clutch is imparted to said stylus arm.

'4. In a sound recording machine including a rotatable disc table, the combination of horizontally disposed guide rails to one side of the disc table and substantially in the plane of a disc on index means and adjusting knob Il may be provided to enable duplication of tension as desired.

IBy permitting the arm 23 to pivot on guide rail 31 (which is on substantially the same level as the record disc being cut), and by permitting the recording head 2| to rise and fall with any undulations in the surface of the discby reason of the shoe 62, the stylus 22 will cut a groove of uniform depth and linear speed.

It is understood that many variations in struc-- ture may be practiced without departing from the spirit or scope of this invention, which is to be determined from, the appended claims. rather than the above description, whichv is intended to be illustrative rather than limitative.

I claim: I

a 1. In a sound recording machine, the combination of: a stationary frame including a horizontally disposed guide means; a pulley rotatably of stationary face plates-ands pair of movable said table, a pulley rotatably mounted on each end of said rails; a flexible continuous band carried by said pulleys; a stylus arm pivotally mounted on one of said guide rails; a clutch including a movable member selectively movable to engage and hold either lay of said band; means connecting said clutch to the stylus arm whereby motion of the clutch drives said stylus arm along said guide rail; a contact shoe carried by the end of said stylus arm; and means for adjustably raising and lowering said shoe.

5. In a sound recording machine including a rotatable disc table, the combination of horizontally. disposed guide rails to one side of the disc table and substantially in the plane of a disc on such table, a pulley rotatably mounted on each.

end of said rails; a flexible continuous band carried by said pulleys; a stylus arm provided with an independently movable stylus head pivotally mounted on one of said guide rails; a clutch including a movablemember selectively movable to engage and hold either lay of said band; means connecting said clutch to the stylus arm whereby motion of the clutch drives said stylus arm along said guide rail; a contact shoe carried by the end 

